Field of the Invention
The present invention relates to operation of an earphone device, and more particularly, to that an earphone connection interface, a terminal including the same, and a method of operating the terminal that can eliminate tick, pop or click noises which occur during the process of releasing an earphone device from the earphone connection interface.
Description of the Related Art
Nowadays, mobile terminals are widely used based on their capability to provide the user with increased mobility. Particularly, a mobile communication terminal that can perform audio dedicated communication while moving is a very popular mobile terminal which most people today use. The mobile communication terminal may also have various functions in addition to providing a function of transmitting and receiving communication information between speakers as a major function. For example, a conventional mobile terminal may have an MP3 function corresponding to an audio file reproduction function and an image collection function corresponding to a digital camera that can collect an image or a function corresponding to a multi media playback. Further, a conventional mobile terminal has a function that can perform execution of a mobile game or an arcade game.
In order to not disturb another person in an audio output process or in order for a single user alone to enjoy audio listening, a conventional mobile terminal provides an earphone system. Accordingly, the user can perform music listening, multimedia playback or broadcasting listening regardless of a time and a place using an earphone device. Here, as a plug of the earphone device is inserted into a cylindrical hole-shaped earphone connection interface of a terminal, a conventional earphone system adapts a system in which the terminal senses connection of the earphone device and activates the appropriate control and sound output functions. Particularly, for support of a microphone for a 4-way earphone device, a conventional earphone system provides a microphone terminal in an earphone connection interface of the terminal and provides a predetermined bias voltage to the microphone terminal, thereby supporting a microphone operation of the connected 4-way earphone device.
However, during a process of releasing the earphone device, because a bias voltage which is supplied to a microphone terminal of the earphone connection interface is maintained during the releasing process, the bias voltage that is provided to support microphone operation induces a tick noise to the earphone device. Particularly, while an earphone left terminal and an earphone right terminal formed in the plug of the earphone device are removed from an earphone connection interface, the earphone left terminal and the earphone right terminal contact with the microphone terminal while being removed and thus the bias voltage is sequentially induced to each of the earphone left terminal and the earphone right terminal and is thus output as noise to each of the earphone output units. Because such tick noise is generally annoying or irritating which a user or a person dislikes, many users experience inconvenience and annoyance when releasing the earphone device.